The invention relates to a cooktop having a plurality of heating elements and a detection assembly for detecting a position and size of at least one cookware element and a method for operating a cooktop.
Cooktops having a plurality of heating elements are known from the prior art, said cooktops being embodied similarly and arranged in particular in a grid or in a matrix. Generic cooktops include a detection assembly, which detects cookware elements placed on the cooktop. A control unit of the cooktop evaluates the measuring results of the detection assembly and combines groups of heating elements, which are arranged in the region of a detected cookware element, into largely freely definable heating zones. The size and shape of the heating zones is therefore flexibly adjusted to the position of the cookware element, which is freely selected by the user, and to the size of the cookware element, whereas in conventional cooktops with unchangeable heating zones, the heating zone is selected as a function of the size of the cookware element. In such matrix cooktops having a plurality of heating elements and freely definable heating zones, a control unit operates the heating elements combined into a heating zone with a heat output, which is determined as a function of a power level set by way of the user interface. If the user sets the highest power level, the heating elements of a heating zone are each operated with the maximum heat output, while with lower power levels, the heating elements are operated with a predetermined fraction of the maximum heat output.
WO 2005/064992 A1 discloses an induction cooktop for instance, in which the total heat output of a heating zone is simulated by the power level selected by the user. The distribution of the total heat output onto the individual inductors complies with the degree of coverage of the inductors by the base of the cooking pot to be heated. Since the sum of the degrees of coverage of the inductors of a heating zone also depends on the position of the cooking pot, this method also does not result in a completely location-independent surface heat output. The calculation and regulation of the heat outputs is also very complicated, since in some circumstances, each of the inductors has to be operated with a different heat output. The different heat outputs may easily result in problems with flickers or intermodulation distortion.
The total heat output of a heating zone, in other words the sum of the heat outputs of the individual heating elements, is therefore dependent on the number of heating elements combined into the heating zone, when the power level selected by the user is the same. The heating elements are then generally assigned to a heating zone, which is adjusted to a specific pot if a degree of coverage between the base of this pot and the relevant heating element exceeds a predetermined minimum degree of coverage. The number of heating elements combined into a heating zone is therefore dependent on a position of the pot. For instance, the same pot can also cover three heating elements in a first position and four heating elements for more than the predetermined fraction in a second position. The unsatisfactory result ensues therefrom for the user in that the same pot is heated with different total heat outputs in different positions on the cooktop when the power level is set the same.